(1) Field of the Invention
The present invention relates to an electrophotographic plate for use in an electrophotographic device or a laser beam printer equipment using He-Ne laser or semiconductor laser, which has a sufficient sensitivity when the wavelength of an illuminating light source is 600 to 800 nm.
(2) Description of the Prior Art
Se electrophotographic plates having a thickness of about 50 .mu.m have heretofore been mainly used in an electrophotographic device or a laser beam printer equipment using He-Cd laser (emission wavelength=442 nm). Such Se electrophotosensitive plate has a sensitivity to short wavelength beams of 400 to 500 nm but has no substantial sensitivity to beams having a wavelength longer than 700 nm. Semiconductor laser devices have recently been put into practical use, and development of so-called semiconductor laser beam printer equipments where writing is accomplished by semiconductor laser has been desired. Since the emission wavelength of semiconductor laser is about 800 nm, conventional Se electrophotographic plates cannot be used for this purpose.
Conventional electrophotographic plates are disclosed in, for example, the following references.
1. U.S Pat. No. 2,753,278 to W. E. Bixby PA1 2. U.S. Pat. No. 3,077,386 to R. M. Blankney PA1 3. U.S. Pat. No. 2,803,542 to O. A. Ullrich PA1 4. C. J. Young, et al., RCA Rev., 15, 469 (1954) PA1 5. E. C. Giaimo, RCA Rev., 23, 96 (1962)